Bangkok, Thailand -- Russian businessman Viktor Bout proclaimed his innocence Friday, accusing the United States of wrongfully portraying him as a billionaire arms dealer with ties to a Colombian guerrilla group.

Bout's wife, Alla, read a statement from her husband -- jailed in Thailand and awaiting extradition to the United States -- in which he denied involvement with the Revolutionary Armed Forces of Colombia (FARC). He said he believed "justice will prevail."

Bout, a former Soviet military officer who speaks six languages, had been indicted by U.S. federal authorities on a series of charges, including counts of illegally purchasing U.S. cargo planes to ferry weapons to warring parties and regimes in Africa and the Middle East.

Thai courts had previously balked at extraditing Bout to the United States on the basis of the original charges against him, which centered on his alleged efforts to send millions of dollars worth of weapons to armed fighters in Colombia. Last year, a Thai court rejected the U.S. government's request for extradition.

Bout was arrested in Bangkok in March 2008 after a sting operation led by agents of the U.S. Drug Enforcement Agency, posing as members of FARC.

Bout, widely regarded as a prolific arms dealer, has been in Thai custody since. He is accused of supplying weapons to war zones around the world -- from Sierra Leone to Afghanistan.

After heavy lobbying from the United States, a Thai appeals court ruled last week that Bout could be extradited.

However, a second extradition request on a separate charge could delay the process.

Washington filed the second case to extradite Bout, according to Thani Thongpakdi, a deputy spokesman for the Thai Ministry of Foreign Affairs, possibly as a hedge if the first ruling went against it.

The United States is now withdrawing it since Bout can't leave the country until any pending cases against him have been settled.

"We are extremely pleased that the Appeals Court in Thailand has granted the extradition of Viktor Bout to the United States on charges of conspiring to sell weapons to a terrorist organization for use in killing Americans," said a statement by acting U.S. Deputy Attorney General Gary Grindler. "We have always felt that the facts of the case, the relevant Thai law and the terms of our bilateral extradition treaty clearly supported the extradition of Mr. Bout on these charges."

But Moscow has been very critical.

Russian Foreign Minister Sergei Lavrov described the Thai appeals court's ruling as an "unlawful, political decision" that was "taken under a very strong pressure from the outside," the Russian news agency RIA-Novosti reported.

The strong criticism has prompted speculation that the Russians are concerned Bout may reveal state or military secrets, RIA-Novosti said.

"I am not in possession of any Russian state military secrets," Bout said in the statement read by his wife. "I have never worked either with Russian companies or state agencies."